I have created a homebrew lich that runs a massive evil necromancy organization in my campaign which revolves around a plague. He is meant to be an extremely tough challenge and is the final boss of a very long campaign. He is extremely old and has gained a substantial amount of power, not only in his own abilities but in the form of magical items. A lot of his character revolves around the chill of the grave, and he is said to be so powerful that just being near him is enough to physically and spiritually exhaust someone. So my question is, have I calculated the challenge rating correctly?

I started with a desire to create a monster with a challenge rating of 25, using the proficiency bonus of +8. He is a 20th level caster of medium size, giving him 20d8's in damage dice and a +100 to hp with his high constitution bonus. His effective hit points are 415 after the bonus for damage immunities and legendary resistances, bringing his defensive challenge rating to 21 with his 19 in AC.

Offensively, he has a very high bonus to hit and saving throw DC with his high Intelligence and the bonus from the Robe of the Archmagi. When it comes to damage output, however, I was very unsure as to how to calculate it because of the complicated nature of spells. I assumed that is must be around 30ish due to the fact that his bonus to hit and saving throw DC are so high they aren't even on the table on page 274 of the DMG.

Taking the average of those results, I assumed the CR to be 25, and 26 with the additional damage capabilities of lair actions.

Did I do this correctly, or is there something I messed up on?

  • \$\begingroup\$ I have added edits to the question. Thanks for the heads-up. \$\endgroup\$
    – Raven Poe
    Mar 6, 2017 at 8:42
  • \$\begingroup\$ I took out the part asking for suggestions, we don't do that here. You could try a forum that we recommend \$\endgroup\$
    – daze413
    Mar 6, 2017 at 8:50
  • \$\begingroup\$ The pessimist in me is saying this might never get a correct answer. Calculating CRs is difficult enough, and it is worsened when: (a) you're brewing a high-level creature, because at that high a level, CR means almost nothing; (b) you're brewing a spellcaster, due to the shifty nature of spells; and at a lesser extent, (c) you add magic items in the equation. Your homebrew creature has all 3. \$\endgroup\$
    – daze413
    Mar 6, 2017 at 8:58
  • \$\begingroup\$ Fair enough. Worth a try. \$\endgroup\$
    – Raven Poe
    Mar 6, 2017 at 9:02
  • \$\begingroup\$ Hi Raven Poe, and welcome to RPG Stack Exchange! Check out our tour to see how we work. I've removed the external link; any important information should be in the question itself — Stack Exchange has a mission to build up Q&A that will be useful in the future, and reliance on external links to make sense of questions and answers generally presents a problem. (What if that Adobe preview link expires next week?) CR check questions are also somewhat turbulent here, but you're welcome to stick around, and when you reach 20 rep you can join us in Role-playing Games Chat. \$\endgroup\$ Mar 6, 2017 at 9:17

1 Answer 1


When computing the damage for any character who deals inconsistent damage (especially spellcasters), average the damage they can do over the first three rounds of combat (assuming everything hits/everyone fails their saving throws). This can be found the instructions for calculating CR, DMG PG 274-279.


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